JIANG Sheng-li1,LIU Zhong1,DENG Hai2 (1.Department of Electronic,Engineering,Nanjing University of Science and Technology,Nanjing,Jiangsu 210094,China; 2.Department of Electrical Engineering,University of North Texas,Denton,TX 76203,USA)

LONG Min1,PENG Fei2 (1.School of Computer and Communication Engineering,Changsha University of Science and Technology,Changsha,Hunan 410076,China;2.School of Computer and Communication,Hunan University,Changsha,Hunan 410082,China)